Zombie PCs exploit hookup site in 4Square-for-malware scam

Security researchers have discovered a strain of malware that uses the geolocation service offered by an adult dating website as an easy way to determine the location of infected machines.

Thousands of infected machines in a zombie network all phoned home to the URL promos.fling.com/geo/txt/city.php at the adult hookup site fling.com, security researchers at Websense discovered. Analyst first thought the adult dating site was been abused as a botnet command and control channel.

Not so.

A more detailed look at the traffic from an infected machine revealed that JavaScript code built into the malware is dues to query fling's systems in order to discover the exact location - state, city, latitude and longitude - of infected PCs.

All indications are that Fling.com is not in on this. Instead, its unsecured geo-location services are being used as a kind of 4Square for zombie PCs. This information is "used by the botmaster for statistics or to give different commands to infected machines in certain countries," Websense explains. The security firm reports that in more than 4,700 samples of these yet unnamed malware behind the attack have been submitted to its security lab to date.

A blog post by Websense, featuring a Wireshark dump of traffic from a deliberately infected machine, can be found here. ®